Fuel cells have been proposed as a power source for electric vehicles and other applications. An exemplary fuel cell has a membrane electrode assembly (MEA) with catalytic electrodes and a proton exchange membrane (PEM) sandwiched between the electrodes. Water is generated at the cathode electrode based on the electrochemical reactions between hydrogen and oxygen occurring within the MEA. Efficient operation of a fuel cell depends on the ability to provide effective water management in the system, for example to control transport of water away from generation sites on the cathode to prevent water build up from blocking flow channels and flooding of the fuel cell.
During operation of a fuel cell at low power loads, product water may accumulate in the channels of the reactant flow fields, particularly on the cathode side. Water accumulation may lead to blocked fluid flow (so called “flooding”) which potentially leads to instability of a portion of a fuel cell. Various means of circumventing this potential problem have been explored and have included altering the physical characteristics of the channels, specifically the channel geometry, including size and shape. Thus, optimum fuel cell performance relates to efficient water management. There remains a need for improved water management to improve fuel cell performance, efficiency, and life span.